Qt5利用自绘QPainter实现旋转按钮MySpinButton

.pro

 1 QT       += core gui
 2 
 3 greaterThan(QT_MAJOR_VERSION, 4): QT += widgets
 4 
 5 CONFIG += c++11
 6 
 7 # The following define makes your compiler emit warnings if you use
 8 # any Qt feature that has been marked deprecated (the exact warnings
 9 # depend on your compiler). Please consult the documentation of the
10 # deprecated API in order to know how to port your code away from it.
11 DEFINES += QT_DEPRECATED_WARNINGS
12 
13 # You can also make your code fail to compile if it uses deprecated APIs.
14 # In order to do so, uncomment the following line.
15 # You can also select to disable deprecated APIs only up to a certain version of Qt.
16 #DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
17 
18 SOURCES += 
19     MySpinButton.cpp 
20     main.cpp 
21     mainwindow.cpp
22 
23 HEADERS += 
24     MySpinButton.h 
25     mainwindow.h
26 
27 FORMS += 
28     mainwindow.ui
29 
30 # Default rules for deployment.
31 qnx: target.path = /tmp/$${TARGET}/bin
32 else: unix:!android: target.path = /opt/$${TARGET}/bin
33 !isEmpty(target.path): INSTALLS += target
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main.cpp

 1 #include "mainwindow.h"
 2 
 3 #include <QApplication>
 4 
 5 int main(int argc, char *argv[])
 6 {
 7     QApplication a(argc, argv);
 8     MainWindow w;
 9     w.show();
10     return a.exec();
11 }
View Code

mainwindow.h

 1 #ifndef MAINWINDOW_H
 2 #define MAINWINDOW_H
 3 
 4 #include <QMainWindow>
 5 #include "MySpinButton.h"
 6 
 7 QT_BEGIN_NAMESPACE
 8 namespace Ui { class MainWindow; }
 9 QT_END_NAMESPACE
10 
11 class MainWindow : public QMainWindow
12 {
13     Q_OBJECT
14 
15 public:
16     MainWindow(QWidget *parent = nullptr);
17     ~MainWindow();
18 
19 private:
20     Ui::MainWindow *ui;
21 };
22 #endif // MAINWINDOW_H
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mainwindow.cpp

 1 #include "mainwindow.h"
 2 #include "ui_mainwindow.h"
 3 
 4 MainWindow::MainWindow(QWidget *parent)
 5     : QMainWindow(parent)
 6     , ui(new Ui::MainWindow)
 7 {
 8     ui->setupUi(this);
 9 
10     MySpinButton *Spin_button = new MySpinButton(this);
11     Spin_button->resize (200, 200);
12     Spin_button->move (10, 10);
13     Spin_button->show();
14 }
15 
16 MainWindow::~MainWindow()
17 {
18     delete ui;
19 }
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mainwindow.ui

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <ui version="4.0">
 3  <class>MainWindow</class>
 4  <widget class="QMainWindow" name="MainWindow">
 5   <property name="geometry">
 6    <rect>
 7     <x>0</x>
 8     <y>0</y>
 9     <width>184</width>
10     <height>188</height>
11    </rect>
12   </property>
13   <property name="windowTitle">
14    <string>MainWindow</string>
15   </property>
16   <widget class="QWidget" name="centralwidget"/>
17   <widget class="QMenuBar" name="menubar">
18    <property name="geometry">
19     <rect>
20      <x>0</x>
21      <y>0</y>
22      <width>184</width>
23      <height>23</height>
24     </rect>
25    </property>
26   </widget>
27   <widget class="QStatusBar" name="statusbar"/>
28  </widget>
29  <resources/>
30  <connections/>
31 </ui>
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MySpinButton.h

 1 #ifndef MYSPINBUTTON_H
 2 #define MYSPINBUTTON_H
 3 
 4 #include <QWidget>
 5 
 6 #define whirlbuttonHeigth   130
 7 #define whirlbuttonWidth    120
 8 
 9 class MySpinButton : public QWidget
10 {
11     Q_OBJECT
12 public:
13     void  paintEvent(QPaintEvent *event);
14     explicit MySpinButton(QWidget *parent = nullptr);
15     ~MySpinButton();
16     void setDegree(int deg);
17     int getDegree();
18 
19 signals:
20     void updateDegree();
21 protected:
22     void mousePressEvent(QMouseEvent *event);
23     void mouseMoveEvent(QMouseEvent *event);
24     void mouseReleaseEvent(QMouseEvent *event);
25     void mouseToPosion(QMouseEvent *event);
26     QSize sizeHint() const;
27     QSize minimumSizeHint() const;
28 private:
29     int degree;
30 };
31 
32 
33 #endif // MYSPINBUTTON_H
View Code

MySpinButton.cpp

  1 #include "MySpinButton.h"
  2 
  3 
  4 #include <QPainter>
  5 #include <QMouseEvent>
  6 #include <math.h>
  7 
  8 MySpinButton::MySpinButton(QWidget *parent) : QWidget(parent)
  9 {
 10     setSizePolicy(QSizePolicy::Minimum,QSizePolicy::Minimum);
 11     degree = 90;
 12 }
 13 
 14 MySpinButton::~MySpinButton()
 15 {
 16 }
 17 
 18 void MySpinButton::setDegree(int deg)
 19 {
 20     this->degree = deg;
 21     this->update();
 22 }
 23 void MySpinButton::paintEvent(QPaintEvent *event)
 24 {
 25     QPainter painter(this);
 26     //反走样
 27     painter.setRenderHints(QPainter::Antialiasing | QPainter::TextAntialiasing);
 28     QTransform tranform1;
 29     int originY = whirlbuttonHeigth/2;
 30     int originX = whirlbuttonWidth/2;
 31 
 32 
 33     const int triangle[3][2] =
 34     {
 35         { originX-2, 0 },
 36         { originX+2, 0 },
 37         { originX, 7 }
 38     };
 39 
 40     painter.setPen(QPen(Qt::red));
 41     painter.setBrush(QBrush(Qt::red));
 42     //绘制多边形，三角形。
 43     painter.drawPolygon(QPolygon(3, &triangle[0][0]));
 44 
 45 
 46     tranform1.translate(originX,originY);
 47     tranform1.rotate(degree);
 48     tranform1.translate(-(originX),-(originY));
 49     painter.setWorldTransform(tranform1);
 50 
 51     QPen thickPen(palette().foreground(), 1.5);
 52     QPen midPen(palette().foreground(), 1.0);
 53     QPen thinPen(palette().foreground(), 0.5);
 54     QColor niceBlue(150, 150, 200);
 55     painter.setPen(thinPen);
 56 
 57 
 58     //随着程度逐渐改变
 59     QConicalGradient coneGradient(originX, originY, -90.0);
 60     coneGradient.setColorAt(0.0, Qt::darkGray);
 61     coneGradient.setColorAt(0.2, niceBlue);
 62     coneGradient.setColorAt(1.0, Qt::white);
 63     coneGradient.setColorAt(1.0, Qt::darkGray);
 64 
 65     unsigned r = 56;
 66     painter.setBrush(coneGradient);
 67     painter.drawEllipse((originX-r), (originY-r), r*2, r*2);
 68 
 69     r = 24;
 70     QRadialGradient haloGradient(originX, originY, r, originX, originY);
 71     haloGradient.setColorAt(0.0, Qt::lightGray);
 72     haloGradient.setColorAt(0.8, Qt::darkGray);
 73     haloGradient.setColorAt(0.9, Qt::white);
 74     haloGradient.setColorAt(1.0, Qt::black);
 75 
 76     painter.setPen(Qt::NoPen);
 77     painter.setBrush(haloGradient);
 78 
 79     painter.drawEllipse(originX-r, originY-r, r*2, 2*r);
 80 
 81     unsigned rx = 30,ry = 8;
 82     QLinearGradient knobGradient(originX-rx, originY-ry,originX-rx, originY+ry);
 83     knobGradient.setColorAt(0.0, Qt::black);
 84     knobGradient.setColorAt(0.2, niceBlue);
 85     knobGradient.setColorAt(0.3, Qt::lightGray);
 86     knobGradient.setColorAt(0.8, Qt::white);
 87     knobGradient.setColorAt(1.0, Qt::black);
 88 
 89     painter.setBrush(knobGradient);
 90     painter.setPen(thinPen);
 91     painter.drawRoundRect(originX-rx,originY-ry, rx*2, ry*2, 49, 99);
 92 
 93 
 94     for (int i = 0; i < 36; ++i)
 95     {
 96         if (i%6)
 97         {
 98             painter.setPen(midPen);
 99             painter.drawLine(5,originY, 10,originY);
100         }
101         else
102         {
103             painter.setPen(thickPen);
104             painter.drawLine(5,originY, 13,originY);
105 
106             tranform1.translate(25,originY);
107             tranform1.rotate(-90);
108             tranform1.translate(-25,-originY);
109             painter.setWorldTransform(tranform1);
110 
111             painter.drawText(22, originY,QString::number(i/6));
112             tranform1.translate(25,originY);
113             tranform1.rotate(90);
114             tranform1.translate(-25,-originY);
115             painter.setWorldTransform(tranform1);
116 
117         }
118 
119         tranform1.translate(originX,originY);
120         tranform1.rotate(-10);
121         tranform1.translate(-originX,-originY);
122         painter.setWorldTransform(tranform1);
123     }
124 }
125 QSize MySpinButton::sizeHint() const
126 {
127     QSize size = QSize(whirlbuttonHeigth,whirlbuttonWidth);
128     return size;
129 }
130 QSize MySpinButton::minimumSizeHint() const
131 {
132     QSize size = QSize(whirlbuttonHeigth,whirlbuttonWidth);
133     return size;
134 }
135 void MySpinButton::mousePressEvent(QMouseEvent *event)
136 {
137     mouseToPosion(event);
138     this->update();
139 }
140 int MySpinButton :: getDegree()
141 {
142     return(degree);
143 }
144 void MySpinButton::mouseMoveEvent(QMouseEvent * event)
145 {
146     mouseToPosion(event);
147     this->update();
148 }
149 void MySpinButton::mouseReleaseEvent(QMouseEvent * event)
150 {
151     mouseToPosion(event);
152     this->updateDegree();
153 }
154 void MySpinButton:: mouseToPosion(QMouseEvent * event)
155 {
156     QPoint currentPoint = event->pos();
157     double pi = 3.1415927;
158     double  x = currentPoint.x() - whirlbuttonHeigth/2;
159     double  y = currentPoint.y() - whirlbuttonWidth/2;
160     if((x ==0)&&(y<=0))
161         degree = 90;
162     else if((x==0)&&(y>0))
163         degree = 270;
164     else if(x>0)
165         degree = atan(y/x)*180/pi + 180;
166     else if(y>0)
167         degree = atan(y/x)*180/pi + 360;
168     else
169         degree = atan(y/x)*180/pi;
170 }
View Code
作者：疯狂Delphi
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原文地址：https://www.cnblogs.com/FKdelphi/p/14654345.html